Dynamic write statements

HI Experts,

Can anybody tell me following answers.

I have

select-options: p_date like Ztab1-date. (we can choose here till 15dates)

low =01/07/07 to high-15/07/07

output screen.

<b>items date1 date2 date3 date4 date5 date6 date7 date8 date9 ..date15 TotalQty</b>

<b>cat1</b> 1000 500 -

700 700 2900

<b>cate2</b> so on

<b>cate3</b>

In write statement: i want my program to decide total qty column should write just select-options range. like if i given in select options 17/07/07 to 18/07/07. my total column should come after next to 2columns, when i given 7 days its shud just next to 7th column,when i given 01st jul 07 to 15th july 07, total come just next to 15th column.

How to do that? Pls sugest.

Thanks in advance.